Enantioselective Multi-Component Cyclopropane Synthesis Enabled by Cu-Catalyzed Cyclopropene Carbometallation with Organoboron Reagent

Deployment of organoboron in lieu of the strongly basic organometallic reagents as carbon source in Cu-catalyzed cyclopropene carbometallation opens unprecedented three-component reactivity for stereoselective synthesis of poly-substituted cyclopropanes. A proof-of-principle demonstration of this novel carbometallation strategy is presented herein for a highly convergent access to poly-substituted aminocyclopropane framework via carboamination. Preliminary results on asymmetric desymmetrization with commercial bisphosphine ligands attained high levels of enantioselection, offering a straightforward access to enantioenriched aminocyclopropanes bearing all-three chiral centers, including an all-carbon quaternary center. This strategy may underpin a host of novel synthetic protocols for poly-substituted cyclopropanes.